cifs: prevent truncation from long to int in wait_for_free_credits

The wait_event_... defines evaluate to long so we should not assign it an int as this may truncate
the value.
Reported-by: Marshall Midden <marshallmidden@gmail.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/transport.c

@@ -523,7 +523,7 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
 		      const int timeout, const int flags,
 		      unsigned int *instance)
 {
-	int rc;
+	long rc;
 	int *credits;
 	int optype;
 	long int t;